In your customer area, at the level of the tab "My account > my orders", you will find at all times all the important information relating to the current status of each/each of your orders/printing projects.
From this screen, you can cancel your order by clicking on the "Cancel" button. Please note that cancellation is only possible if the order is in "Awaiting payment" or "File check in progress" status. Once the order is in production or shipped, it is no longer possible to cancel it.